With means available, cancer can be cured if diagnosed early, before cancer has spread too far. The early clinical findings require a biopsy for a diagnosis. The pathologist can (1) exclude cancer; (2) find changes, leaving no doubt as to the malignant nature -- the cancer may be then already invasive; (3) anaplasia may be moderate; or (4) cells with criteria of cancer may be close to normal cells (carcinoma-in-situ). It was established that some lesions of this type may be reversible. Treating such patients as having carcinoma may lead to unnecessary surgery. On the other hand, failure to be radical may deprive such patients of the benefits of surgery. The highly sensitive and specific Red Cell Adherence (RCA) test detects the A, B and H antigens in tissues and permits (1) to diagnose some carcinomas earlier than any other method. The quantitative test which we developed increases the sensitivity of the adherence test. We will continue to test our results by studying prospectively and retrospectively a larger number of early and advanced cancers in different organs.